Indicator warning light constantly on in instrument panel

[seriouseng]

Hi folks,
I have a issue with the indicator warning light on the instrument panel being constantly on but not flashing once the ignition is turned on nor does it repeat when the indicator switch is moved to right or left hand indicator position just a steady green light.
I had just replaced the original bulb 12v 3w push fit type as that had blown at some point in the bikes life , I don't know how long the issue has existed as it never worked when I bought the bike last year and it's been going through a rebuild since then.
Strange thing is it lights up as soon as the ignition switch is in the running position regardless of the position of the kill switch ie on run or on off positions.
Seems to have a constant live feed , unfortunately this is the 1978 model r80/7 with the buzzer option wired in the loom, however it's not functional and has no relay or buzzer fitted .
Indicators work fine so not big issue but looking for clues on what may cause this , I know the buzzer relay if fitted gets it's power from coil feed.

[gspd]

You need to dig up a wiring diagram and do a bit of circuit tracing with a test light.
Should be relatively quick and easy in person (but usually long and tedious if done remotely in absentia).
Maybe Rob F will chime in and give you a few pointers (and maybe wiring a diagram).

[Rob Frankham]

I think your bike has a four terminal relay (away from home at the moment so I don't have my reference sources to hand). If that is the case, it's about 90 to 1 that the fault is the indicator relay. These relays have a completely seperate circuit to handle the indicator repeater and this can completey fail without affecting the main flasher circuitry. The four terminal relays are pretty expensive but the only solution is replacement... or... a quick mod which will allow the use of a standard 3 terminal relay. If you want to try the mod, let me know and I'll try to find the details but it mwy have to wait till I'm home...

Rob

[seriouseng]

Thanks Rob ,
Can I take you up on that offer of how to do the modification please.
In the interim I will dig up a wiring diagram , I think there is a link to one on Snowbums web site .
Thanks both I'll let you know if I find anything .
Cheers Kev

[gspd]

Power to left turn signal is BLUE/RED
Power to right turn signal is BLUE/BLACK
Power to dash indicator is BLACK/WHITE

Do a bit of tracing to determine why the BLACK/WHITE always has power.
Maybe something is shorted or wrongly connected.

If there is actually a faulty circuit inside the relay and you don't want to replace the relay, connect the BLACK/WHITE to the flasher feeds.
You'll need two 5W diodes (basically a one-way valve) so the left side doesn't feed back to the right side and vice-versa.
These diodes can be had for pennies at any electronics store.

This will work, but wait to see if RobF can devise a simpler solution.

[seriouseng]

Thanks for that fix , cant see why it would not work.
changing the subject slightly but sticking with diodes , i came across this fix in the headlamp shell to bypass the diode on the fuse/connector board in headlamp should the diode on the board go , you can see that a jumper cable has been made up with diode soldered in line and a double spade at one end ( think it was the neutral switch side rather than the starter switch side due to diode direction ) . I will be keeping this bypass cable for temp repair on the roadside.
As you can see one of the previous owners loved yellow cable and crimped connectors which i have removed and made good now in headlamp .

bypass-1.PNG (1.1 MiB) Viewed 1090 times

Fuse board rear no diode.PNG (745.97 KiB) Viewed 1090 times

Junked .PNG (783.54 KiB) Viewed 1090 times

[Rob Frankham]

As I'm reading the diagram, the right is linked to one side of the repeater and the left is linked to the other. This won't work for two reasons... 1) one side of the repeater is hard wired to ground inside the instrument cluster and 2) each diode would block the current flowing through the other. The way to do it is to take the two diodes and link the anodes together (the anode is the end of the diode with the white or silver band). The linked anodes are then connected to the wire to the repeater. The cathodes (i.e. the other ends of the dioes) are linked to the right and left indicators respectively. Very simple and just a 'dongle' that fits inside the headlamp shell. As I said, I have a diagram... but not on this computor.

Or perhaps I'm misreading the diagram and it actually shows what I am saying...

Rob

[gspd]

I omitted the pre-existing ground circuit in my earlier diagram.
The 2 lines going into the dash indicator are one wire. (my way of drawing one Black/White wire)
I thought I drew the diodes to show that power can flow in to the dash indicator but not out of it.
Does this make more sense?
Activating either flasher will light the dash indicator, no?

[seriouseng]

Hi Gents ,
I've seen a similar mod using two 30v 5a diodes and a switch to create a hazard flash option on systems without that facility.
That takes it's power from the lamp side of the flasher relay with a switch inline then it links to the RH indicators side via a diode 30v 5A and same for LH side via another 30v 5A diode but you needed to add it's own indicator light .
But that was for a 3 pin relay .

[Rob Frankham]

I omitted the pre-existing ground circuit in my earlier diagram.
The 2 lines going into the dash indicator are one wire. (my way of drawing one Black/White wire)
I thought I drew the diodes to show that power can flow in to the dash indicator but not out of it.
Does this make more sense?
Activating either flasher will light the dash indicator, no?

My misreading, I was seeing the thick and the thin black lines as seperate wires. With the earth clarification, the diagram is exactly what I was describing.

Rob